Electric smelting-furnace.



l E. 11. TAYLOR.

ELECTRIC SMELTING PURNACE.

APPLICATION FILED JULY 7,1910.

- 985,226. Patented 11911.28, 1911.

5% lll/m l E. R, TAYLOR.

ELECTRIC SMELTING FVURNACE. APPLICATION FILED JULY 7, 1910.

985,226. Patented Feb. 28, 1911.

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atbo'anu E. P... TAYLOR.

ELECTRIC SMBLTING FURNACE.

`APPLICATION FILED JULY 7, 1910.

. 985,226. Patented Feb. 2s, 1911.

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11. R. TAYLOR.

ELECTRIC SMELTING EURNAGE.

APPLICATION FILED JULY 7, 1910.

985,226. e Patented Feb.28,1911.

8 SHEETS-SHEET 4.

E. R. TAYLOR.

ELECTRIC SMELTING FURNAGE.

APPLICATION FILED JULY 7, 1910.

985,226. Patented Fenza, 1911.

8 SHEETS-SHEET 5.

E. R. TAYLOR.

.ELECTRIC SMELTING FURNACB.

APPLIGATION FILED JULY 7, 1910.

Patented Feb. 28, 1911.

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Gttoznut E. R. TAYLOR.

ELECTRIC SMELTING PURNAGE.

APPLIUATION FILED JULY 1, 1910.

Patented Feb. 28, 1911.

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E. R. TAYLOR.

ELECTRIC SMELTING FURNAOE;

APPLIATION FILED JULY 7,1910,

UNITED STATES PATENT OFFICE.

nnno'rnic sMnLTING-runnaon.

Specification of Letters Patent.

Patented reuze, i911.

Application filed July 7, 1910. Serial No. $70,836.

To all whom it may concern:

-Be it known that I, EDWARD R. TAYLOR, a citizen of the United States ofAmerica, and a resident of Penn Yan, in the State of New York, haveinvented a new and useful lmprovement in Electric,Smelting-Furnaces, ofwhich the following is a specification This invention relates primarilyto the electric smelting of oxid iron ores by a continuous process; butthe yimproved electric furnace, and novel features thereof, may be usedlfor effecting other reactions and reductions The 'present inventionconsists in the im` proved electric furnace hereinafter described, andcertain novel combinations of parts therein, as more particularly setforth in the claims hereto appended.

l This invention is additional to the improvements in electric furnacesset forth in my previous specifications forming part of United StatesLetters Patent No. 688364,

' dated December 10, 1901, and No. 938,351,

datedOctober 26, 1909.v The latter is hereinafter referred to as mycompanion speci fication.

' tween them; the prevention of the leakage of electricity, Vwithreference to securing the maximum heating or electrochemical effect ofthe current; the interception andfutilization to the utmost of heat thatwould otherwise be lost by radiation, and the avoidance of the coolingof the more highly heated inner part of the furnace in continuousreactions and reductions by the sudden introduction of cold material, soas to insurethe continuitjk of the operation; the utilization in aneffective manner'of the alternating or two-phase electric current insuch furnaces; and provision for varying vthe paths of the electricitythrough the charge within the working chamber so as to revent theformation of piers of the ess fusible ingredients of the charge, or toburn out such' piers should they accidentally be formed.

Other objects commento the'subject mat- Ater of said companionspecificationrand the present invention are to meet and overcome certaindifliculties that present themselves in the electric smelting of metalsand other electrically conductive materials in a shaft furnace, andespecially to keep the material of the charge between the electrodesfrom becoming so conductive of electricity as to reduce the resistanceof the furnace below practical working limits; to separate the ore inthe four quarters of a two-phase furnace of the preferred staclr typeand to keep the same separate, and thus .to facilitate the manipulationof ore within the furnace; to provide for employing a large proportionof fine ore such as cannot be smelted in a blast furnace because of itsliability to be blown out of the furnace by the blast; to provide forfeeding fine and coarse ore downward in a stack fiirnace in separatevertical or substantially vertical columns; to utilize rportions of thefine ore columns for the conservation of the heat of the furnace; to soregulate the feed ofthe ore as to properly utilize the energy liberatedbetween the main electrodes lwithout causing short circuits; toA:.provide for admitting successive small quantities of line ore intothe outer edges of the coarse ore columns on their way to -the heatzone; to provide for feeding suitable drycarbonaceous material for thecharge, preferably either coke or charcoal, in a central column, and forutilizing lateral wings of such coke column, as it is hereinaftertermed,to separate the columns of coarse ore; to utilize such coke column as aresistance conductorbetween secondary electrodes located at the bottomand top of the furnace respectively; to provide in this way for startingthe furnace with facility by the interaction of said secondaryelectrodes and said coke column; to keep thery carboiiaceous material ofthe charge vincandescent to agreater height than has heretofore beenpracticable; to vary the height of such incandescence at will; todetermine thus the percentage of carbon, for example, in the reductionof iron ores, so as to produce pig iron or steel as may be desired; toinsure the formation of the weakest point in the. main circuit betweenseid horizontal electrodes at all times; to utilize the heat at thispoint for superheating the streams or globules of fluid metal as theytrickle downward, so that they shall carry with them into the hearthsuffit, cient heat to keep the metal in the hearth in 'a fluidcondition; to provide for reheuting the metal in the hearth in case ofaccident; to reduce ore to metal to as considerable an extent as may bepossible in the fine ore before it reaches the heat zone; to promote-thereduction of oXid iron ore by the circulation of the gases within thefurnace, and to provide for the introduction of air or other oxidizingmaterial into the center of the furnace, to burn out fortuitousaccumulations of carbon or other oxidizable material which may interferewith the regular working of the furnace.

The leading objects peculiar to the present improvement are to providefor building the improved furnace with a cylindrical upper feed portionas compared with the downwardly flaring feed portion heretoforeproposed, and thus to form vertical feed passages for the heatconserving streams of ore on its way to the heat zone and to accommodatefeed hoppers, ne-ore passages and a gas chamber of relatively largecapacity in a furnace of given diameter; to provide for subdividing thefine-ore passages, and insuring more positively the intermixture of thefine ore with the coarse ore on their way to the heat zone; to combinean upper cylindrical feed portion of large horizontal area with arelatively small hearth, without the aid of mechanical stroking means,or with Such aid as the character of the gravity-fed material of thecharge may demand; to dispense with metallic stems for horizontalelectrodes of large size; to provide better means for keeping the innerends of such electrodes at the most effective working distance apart;and to utilize such electrodes as means for the introduction ofoxidizing material into the center of the working chamber to burn outfortuitous accumulations of carbon or other oxidizable material asaforesaid, or for other purposes.

Other objects will be set forth in the general description whichfollows.

Eight sheets of drawings accompany' this specification as part thereof.

Figures l and 2 represent axial vertical sections in different planesthrough an electric smelting furnace embodying the present invention,and illustrating the smelting process; Fig. 3 represents the samevertical section as Fig. 2, showing the furnace empty; Figs. l and 5 areplan views respectively of the top ofv the furnace above and beneath itstop plate, indicating by lines A-B and C-D the planes of Fig. l and ofFigs. 2 and 3, respectively; Fig. G representsk a horizontal section onthe lines E-F and FIL-F', Figs. l and 2 and Fig. V8; Fig. 7 represents asectional elevation on a larger scale of a reciprocating stolrer; Fig. 81s an axial vertical section, corresponding mainly with Fig. 2, showingrotary stoking screws; Fig. 9 re resents an axial section correspondingmain?) with Fig. l, on a smaller scale illustrating the employment ofinclined main electrodes and showing more fully the means for feedingthe main electrodes; Figs. 10 and ll are sectional detail views showingthe construction of electrode clamp and gas check represented in Figs. land 9, and the preferred construction of the main electrodes; andl*`igs.` l2 and 13 are respectively a side elevation and a cross sectionof the electrode feeding device represented in Fig. 9.

Like reference characters indicate like parts in all the figures.

The improved furnace is of a staclr form; its internal structure, a,being built of suit- Yable heat-resisting material, such as brick orcement, within a metallic shell, b, of iron or steel, hereinafterreferred to as iron; and a layer, c, of a suitable incombustiblenon-conductor of electricity, such as asbestos, is interposed betweenthe internal structure a and the shell b throughout.

The top plate, (Z, of the shell and of the furnace is convenientlyhorizontal, and is provided with feeding hoppers, e, f, g and it, bestshown'in Fig. ll, which are conveniently so shaped and so united witheach other and with the top plate as to form a truss by which thesubjacent top-plate is stifiened against sagging. The respective hopperse, f, g and h communicate with the upper ends of Hue-shaped passages,z', j, .Za-7c and Z, which extend downward within the internal structurea, and the hoppers f and passages y', each of them four in number, inthe specic construction represented by the drawings, are appropriated tothe principal charge of ore, hereinafter referred to as the coarse ore,which is thus divided into several distinct columns. Another set`ofhoppers and passages, g and c-k, ex.

tei-nal to said coarse-ore passages, are appropriated to fine ore, andthese tine-ore passages /c-c are divided into main passages (fr) andperipheral passages (c) by hollow walls, forming a gas space, m, withineach wall open at bottom and also in direct communication with theworking chamber, n, by way of outwardly flaring gas tubes, 0. The

peripheral fine-ore passages, 7c" communicate with the working chamberat their lower ends only, and are located peripherally, as shown inFigs. 2, 3 and 6, so that the body of fine ore witliin them may be ascool and as continuous as may be practicable, with reference tointercepting and utilizing radiant heat. The main fine-ore passages, 7n,are provided with baffle plates, p, Figs. 2 and 3, preferably V-shapedin cross section Y and arranged with the apex uppermost so as to retardthe flow of the fine ore to a sufficient extent, and to form suitablydistributed gas spaces through the body of fine ore.

The central hopper e and the passage z' extending vertical 1 therefromare approprireferred to as eolie.

top of the furnace', and this wall is supported by partition/walls intheform of iying buttresses arranged in pairs around said central Wall, andforming v'between them where their inner edges are Iexposed below saidcircular wall, a wing-shaped passage, t", in communication with saidcentral passage z' above each of the main electrodes, so that the cokemay spread laterally in the form of wings between and below' saidpartition walls and extend the separation of the columns of coarse oreto the heat zone, -The other four of said hoppers, shown at It in Figs.1 and 4, and the peripheral passages, Z, leading downward therefrom,betweenv said wingshaped coke passages z" and the outer wall of thefurnace are appropriated' to the feed of resistanceregulatingxnaterial.adapted to flow downward by gravity and toprotectthe main electrodes and regulate the conductivity of the chargeat the'heat zonel as set forth in the previous specificationshereinbefore referred to. I still prefer as such material brokenvelectrode carbons reduced to suitable fragments by crushing, whichinsures a regulatingI material of greater conductivity than the chargeofcoke or charcoal. Said main electrodes g, r, s, and t are preferablyfour innumber and arranged intwo pairsat right angles to each other iand horizontal as aforesald, and are'located immediately above'thehearth, u. Secondary electrodes, v and w, are located respectively atthe bottom and top of the furnace; the bottom electrode, fu, having acarbon body, 9, which forms a lining for the hearth u of the furnace,and is provided with a depending water-cooled metallic stem, 10.-

Such stem is suitably connected with water circulating pipes 18 and 19,the details of whiehmay be of anylrnown or improved description, andprotrudes through a watercooled stuihng-box, 20. The secondaryelectrodes, w, at the top of the furnace are preferably four in number,located above the respective main electrodes g, r, s and t, and themetallic stem, Q7, of .each of suchtop electrodes extends upward throughYa' watercooled stuliing box, 28, on the' top l.plate d as shown inFigs. 1 and 4. The carbon bodies of the top electrodes are'supportedsubjacently within pockets, 29, Fig. 1,

formed in the walls of the fmtral colte passage z', so that the face ofthe carbon body ofeach of these electrodes is substantially Hush with'the inner surface of said wall, and c sets of electrodes, that is tosay the main Said coke passage z' is formed by a central circular wallat the electrodes, g, r, s, t, and the secondary elec* trodes, o, w, arepreferably connected elec trically with different dynamos; and thelatter are preferably ofthe two-phase or alternating type for the mainelectrodes, at a least'.

The hearth u is provided with an outlet,

30, through which to run olf the fluid meal,

and an outlet, 31, ata higher point,'for

molten slag. The hearth portion of the furnace is suspended from an-annular metallic sill, 32, which may rest upon columns or the like incustomary manner, andl the depending portion of the hearth is preferablyprovided with a water jacket, 33, provided with suitably located inletand outlet connections, 34 and 35, Fig. 1. i

`An annular gas chamber, 36, Figs. 1 and Q, atthe top of the furnace,communicates freely with the coarse-ore and coke massages, and with theintermediate passages for fine ore and regulating material, anddischarges through an outlet pipe,37, Figs. 1 and 4.

The tubes 0, for circulating the CO and C()2 gases within the furnace,extend from the coarse-ore passages y', outward into curbs, 38', whichproject inward to thevgas spaces m from outside the furnace; and rotaryblowers, 39, in the form of electric fans, are located withi'n the outerends 'of said tubes and driven by electric motors, attached to the ironshell bof the furnace; the blower tubes 0 being so located as te keeptheblowers `from opposing "one another.

The line-ore passages 1:-70 and gas spaces m terminate at bottom in openends within arched recesses, y, Fig. 3, and all the feed passagesdischarge into the working chamber by gravity. i

To insure the inward feed of the ore to a sufficient extent, suitablestoking means may be provided beneath the several fine ore passages 7cand such means may consist of stoking screws, e, Fig. S, rotated bymeans of worm gearing-40, which may be driven by hand cranks or byelectric motors; such screws a having their main bearings inwater-cooled stuling boxes, 41, and outer bearings within yokes, 42,attached to the 46', to prevent the passage of the electric cui" rentoutward through the screws. rihe inlet and outlet waterconnections ofeach stuffing box 41 and each water-cooled frame 44 are representedrespectively in Fig. 8 at'47-48 and 49-50. The openings capped by theface-plates 43 and through which the stolnng screws are inserted endwiseinto thcfurnace and withdrawn for renewal or repairs are represented at51 in Fig. 8.

Passages, 52, Figs. 11, 12 and 13, with suitable connections, areprovided, through which air or other suitable oxidizing material may beblown into the center of the working chamber n at will.

One or more man holes, 57, Figs. 2, 3 and S, suitably capped, andconveniently located, provide for entering the furnace after the'working chamber and hearth are emptied and cooled for the renewal orrepair of the electrodes and other like work, and may also be utilizedin arranging the charge preliininarily.

In preliminarily charging the furnace, the hearth u is filled with coke,and a column of coke is built up within the working chamber n surroundedby coarse ore to a suiiicient height to insure the completion of acontinuous coke column extending from the bottom electrode v to a pointmore or less near the upper ends of the top electrodes fw.Simultaneously,lafter the plane of the main electrodes, g, 7, a, t, isreached, fine ore may be fed in through the line-ore hoppers, g, untilthe fine-ore passages, .7c-Jo, are filled or substantially filled. Thepassages, 1, for regulating material, above the several main electrodes,g, 7', s, t, may be lled at the saine time or subsequently, and thestreams of regulating material may be suitably directed over and incontact with the main electrodes, as shown in Fig. 1. The electriccurrent is turned on, first through the secondary electrodes o and w,and through the intervening column of coke, which is thus renderedincandescent. The current is then turned on through the main electrodes,q, 71, s, t, and its supply to both sets from dierent dynamos asaforesaid, may be simultaneous throughout the reducing operation, or thesecondary electrodes, o-fw, may be used only occasionally as required.

The height to which the central coke column is kept incandescent may bedetermined by passing more or less current therethrough by way ofsaidsecondary electrodes as required, and that in turn determines theproportion of carbon in the molten metal as it reaches the hearth,and'facilitates producing either pig iron or steel at will. The gascirculating blowers, ma, are started as soon as the coke column isincandescent, so as to insure the conyersion of the carbonic-oxid gas(CO) formed in the vicinity of the heat zone into carbonio acid (CO2),the conversion of the latter into caibonic-oxid gas again, and so onalternately. Suitable fluxes are added to the several columns of ore andpossibly to the coke, as may be required, and

the supply of materials by way o'f the several hopp`ers, c, f, g, h, atthe top of the furnace, is kept up so as to render the operation of thefurnace substantially continuous.

Stoking may be resorted to occasionally as may be required to render theoperation.

of the main electrodes, g, r, s, t, substantially uniform; as well as toregulate the feed of the fine ore inward to the heat zone.

The Huid metal is run off from time to time or continuously through thetap hole, 30, Fig. 1, and the molten slag through its outlet 31, Fig. l.The discharge of gas through the pipe 37 at the top of the furnace maybe continuous,land may, if desired, be promoted by an exhaust fan; thegas being stored, for use in engines or otherwise, in known or improvedways.

The electric connections may include suitable switches for varying theflow of the current through the main electrodes, g, 7', s, t, asillustrated by Fig. 12 of my Patent No. 702117, dated June 10, 1902; andin like manner provision may be made for discon necting the mainelectrodes from their normal source of supply and throwing them intocircuit with the bottom electrode v, in order to melt out the contentsof the hearth u after temporarily suspending the operation.

The features of construction and mode of operation aboveibrieflydescribed are coinmon to the' present furnace and that set forth inAsaidy companion specification, and any and all patentable combinationsof parts above particularly described are hereby disclaimed in favor ofthat specification and kthe other previous specification hereinbeforereferred to.

In the present furnace the entire superstructure above the hearth iscylindrical eX- ternally, and in the upper feed portion the outer walls1 .and 2 are cylindrical instead offlaring downward as heretofore.

A topplate d, confined substantially as heretofore to the diameter ofthe top of the passage-forming body a of the furnace, forms thus ahopper floor of largely increased area; and a relatively wide gaschamber, 36, beneath said top plate and above the closed upper ends ofthe hollow walls- 2, is formed without special construction between thecircular walls 1 and 3. The partition walls 5, 0, 7 and 8, which connectthe circular walls 1 and 4, are preferably and conveniently extendedupward to the top plate as shown in Fig. 5. The gas chamber 3G is thusdivided into several compartments, which are-connected with each otheras with the spaces above the coke-column wings and coarse ore columns byholes 11 and 12, Figs. 1, 2 and 3, formedin the inner wall 3 and in saidartitions respectively. More particularly, said cylindrical feed portionand said cylindrical outer walls ,1 and 2 render vertical the peripheralfeed. passages, 7u', for fine ore, and accommodate between the same andthe downwardly flaring inner wall 3 a main feed passage, lc, for lineore,

of largely increased capacity in each quarter of the furnace. Said maintine-ore passages l.; are subdivided to any required extent bypartitions, 13, Fig. 2, etc., of sheet metal or other suitable sheetmaterial, suspended by bolts, 14, from. the top plate zi, and supportedat their inwardly extending lower ends by ledges, 15, on the inner wall3, immediately beneath openings, 16, of ample size in said inner wall,through vwhich the several partitions direct their streams of fine oreinto the outer edges of the coarse-ore columns, so as to mix with thecoarse ore in transit any desired proportion of fine ore, for exposuretherein to the CO and C()2 gases passing back and forth through thecoarseore columns into and out of the incandescent coke column.

In thespecies represented by Figs. 1 to 6 inclusive, with the aid ofFigs. 10 to 13 inclusive, mechanical s'toking means are dispensed withby the employment in their stead of inclines, le', beneath the severalcolumns of resistance regulating material and also beneath the severalfine-ore columns, as shown respectively in Fig. 1, and in Figs. 2 and 3;such inclines being conveniently built as part of the passa e-formingbody a, with or without dead air chambers, .17, and with their effectivefaces in line with the sides of the hearth, u. Such inclines will inmost cases sutlicefor bringing the material in toward the center of theWorking chamber, owing to the weight of the body of material above themvand the absence of any obstruction to the inward movement of the ore.

lThe main electrodes q 1' s t of all the species of the present furnaceare stemless, asshown in Fig. 1 and Figs. 9 to 13 inclusive; eachelectrode consisting, as a Whole, of a solid or substantially solidrectangular body of suitable electrode carbon.. Special provision isrequired for the employment of horizontal electrodes of this form, owingto the size and weight required in a furnace adapted for reducing ore ona .commercial scale. Each electrodeis accordingly supported beneath, asnear as practicable to its inner end, by a trunnioned horizontal roller,21, preferably molded of suitable lire clay or cement and burned orbaked; said roller having bearings of like or other suitable material inthe floor of the embrasure, 22, in the. body a through which theelectrode extends inward. For closing the coincident opening', 23, inthe furnace shell b around each electrode against. the entrance of airand the escape of gas, and so as to rovide if desired for thetransmission of t e electric current by the same means, a rectangularmetallic collar, a', is employed including .a frame, 24, Figs. 10 and11, fixedly attached to the shell b and insulated therefrom, andprovided internally with movable wat rig. a

sections, 25-25, adapted to maintain the required contacts with theseveral sides of the electrode, with the :trame and withfeachother'under different adjustments, together with means for retractingsuch sections to free the electrodes, in the Aform of screws, 26,parallel with the'electrode. The frame, 24, may conveniently beconstructed with a cooling chamber, 24', Fig. 10.

An electrode collar of above general description is shown in detail byFigs. 10 and 11, which see. The sections 25-25 in this specificconstruction are eight in number, and include corner sections, 25, whichclamp the several corners of the electrode and side sections, 25', forthe several sides constructed to interact with said corner sectionsas'clearly shown in Fig. 1l. The number of such sections may vary, andthe construction of an electrode collar on the same principle may followmany lines as to details of construction. The construction oi theelectrode collar will ,be made the subject matter of a separate patentspeciiication. Such electrode collars a1 may constitute the means forconnectinon the several main electrodes with the cables leading from thedynamos as indicated at 23 in Fig. 1, or they may practically n.sz'tu,and for feeding them lengthwise through the electrode collars asillustrated by Figs. 12 and 13 in connection Such means include endwisemovable molds, Z5', adapted to be used in the building up operation andalso for feeding the electrodes through said electrode collars a. Eachof these molds l5 includes a horizontal platform 53, and relativelyremovable side and top members 54e and 55, togethei` with transverseclamps, 56., provided with jack screws, 58 and459, which areperpendicular to said side and top members respectively when the latterare in place as in Figs. 12 and 13. The mold b is conveniently mountedon car wheels, 60, 61, having axles transverse to the mold and to theelectrode, which run on rails, 62, beneath the electrode, leading to theadjacent side of the furnace and supported by a suitably insulated loor,c'. This floor also supports, in

suitable bearings, 63, a horizontal shaft, G4, carrying a pinion, 65,betwecn said rails, which is in mesh with a rack, 66, on the bottom ofthe mold platform. Suitable means for rotating such shaft may consist ofWorm gearing, 67, connecting it with the shaft 68 of a small electricmotor, d', or its equivalent. The mold b moves bodily forward nwith theelect-rode in the feeding operation.

It is Shown in Fig. 12 as it appears immediately after having beenclosed and before moving it to any appreciable extent. After the mold ismoved in successive feeding operations until its rear wheels 61 reachsaid feed shaft 6ft, the mold is taken apart by re` moving said clamps56 and removable members 54 and 55, and the operation of building theelectrode is resumed.

Each horizontal electrode is composed of a large number of relativelysmall umts, 69, 70,'Figs. 11-13, rectangular in cross section, includinga central tubular unit, 70, to forni said passage 52 for theintroduction of ok.- idizing material. This tubular unit is preferablyand conveniently composed of relatively short sect-ions, 70', Fig. 12,ot fire clay or the like, so as to be incombustible and at the sameltime adapted to be kept open by the sloughing 0H which occurs at theinner end of the electrode. The other units, 69, are of suitableelectrode carbon. l'n building up the electrode, the platform 53 of themold 7) having been exposed and properly located for this operation, theunits are built up thereon layery by layer; care being taken to have thesections or lengths of the carbon units 6i? break joint longitudinallyas at the right in Fig. 12, and a suitable carbon cement, which may becomposed of ground carbon and molasses, is spread between the layers asthe. work progresses. The operation proceeds in this manner until asufficient length has been built up to fill or refill the'mold b. Theside and top pieces 54 and 55 of the mold 5 are then applied', beingfirst loosely held in place by the retracted jack screws of the clamps56, and ultimately brought together and to gage, as in Fig. 13,by-tightening the jack screws 58 and 59 in proper order so as to renderthe electrode rectangular and of the required dimensions. The mold isnow ready to be used in the feedingoperation, as above described, andwhen it has again reached the position represented in Fig. 12 it isagain retracted and the building operationresumed, and so onindefinitely."lt is of course necessary to stop the current for renewingthe" electrodes, but this involves very little delay-in working the'furnace as compared with the withdrawing and replacing of horizontalelectrodes as heretofore constructed.

The modification represented by Fig. 7 consists in the substitution forsaid inclines e', Figs. 2 and 3, beneath the several fineoie passagesc-c and for the rotary stoking screws z, Fig. 8, of a reciprocatingstoker, z2, beneath each fine-ore passage, or, preferably the rovisionof each of said inclines z beneat the fine-orc passages with a stoker z2of this form, if the ore to be treated needs suchmeehanical stoking. Thespecic stoker represented consists of a cylindrical plunger, 71, Fig. 7,and an open ended cylinder, 72, which may be molded of tire clay or asuitable cement com osition, an external frame, 7 3, bolted with saidcylinder to the furnace shell b, a stem, 74, attached at its inner endto said plunger and having a screw-threaded outer end, a rotatable nut,75, in the form of a worm wheel, means for rotating said nut including aWorm, '76, in mesh with its worm teeth, and a stufling box, 77, formingpart of said frame. The plunger 71 is shown at the inner limit of itsstroke. Having reached this position it is run back within the cylinder72, and again advanced from time to time as required. The shaft of saidworm 7G may be that of a small electric motor or' any preferred drivingmeans."

The species represented by Fig. 8 maybe identical with the first speciesrepresented by Figs. 1-6 and Figs. 'A10-13 excepting its rotary stokingscrews .e and their accessoiies already described.

In the species represented by Fig. 9 the horizontal electrodes, two ofwhich are shown at g and r, are of the inclined type, arranged to dip inthe slag at the top of the hearth u more or less as desired, and thefigure illustrates the adaptation of the electrode collars a and feedingmeans b-d, Figs. 10-13, to control such inclined electrodes of anyrequired size. For the accommodation of such electrodes the body a andshell Z) are modified so as to form inclined seats, 78, at right anglesto embrasures, 22', of the required slant; and so as to form suitableinclines, 79, above the several electrodes down which the resistanceregulating materialwill flow from the passages Z. Otherwise all thefeatures of construction represented in Fig. 9 have already beendescribed with reference to Figs. 1-6 and Figs. 10-13.

Excepting the novel combinations of parts above described andhereinafter claimed, the present furnace is preferably-of theconstruction more particularly set forth in said companion specificationand its accompanying drawings, but for the purposes of the presentinvention may be of any known or improved construction consistent withsaid novel combinations of parts respectively.

In operating the furnace some of the blowers m may be reversed withreference to the others so as to insure the circulation of the CO andCO2 gases in the most effective manner, includingthe return of the gasesfrom the upper part of the working chamber to lower planes where thetemperature of the ore is appropriate to immediate reduction of ore tometal; and other like modiiications in the operation of the furnace asin its construction will suggest themselves to those skilled in the art.i

Having thus described said improvement,

I claim as my invention, and desire to patent under this specication:

l. An electric smelt-ing furnace of the stack type having, incombination, a` suitable hearth, a superstructure of suitableheat-resisting material inclosing a working chamber above the hearth andconstructed with a cylindrical upper feed portion including acylindrical outer wall and cylindrical walls concentric therewithforming between them vertical feed passages for heat-conserving streamsof ore on its Way to the heat Zone, a centra-l circula-r wall inclosinga vertical flueshaped coke passage and a downwardly ilari'ng circularwall sepa-rating inner and outer ore passages surrounding said cokepassage, and horizontal electrodes extending` into the working chamberimmediately above the hearth; said passages discharging in common intothe working chamber by gravity.

2. An electric smelting furnace of the stack type having,. incombination, a suitable hearth, a superstructure of suitableheat-resisting material inclosing a working chamber above the hearth andconstructed with a cylindrical upper feed portion including a.cylindrical outer wall and c ylin drical walls concentric therewithforming between them Vertical feed passages for heatconserving streamsof ore on its way to the heat'zone, a central circular wall inclosing avertical lue-shaped coke passage and a. downwardly flaring circular walland radial partitions separating and dividing inner and outer orepassages surrounding said coke passage, and horizontal electrodes eX-tending into the working chamber immediately above the hearth;said'passages discharging in common into the working chamber by gravity.

, 3. An electric smeltingI furnace of the stack type having, incombination, a structure of suitable heat-resisting material inclosingthe working chamber and constructed with a cylindrical upper feedportion including a cylindrical outer wall and cylindrical wallsconcentric therewith forming between them vertical feed passages forheat conserving streams of ore on its way'to theV heat zone, a centralcircular wall at the top of the furnace vinclosing a vertical flueshapedcoke passage and a downwardly ilaring circular wall-separating inner andouter ore passagessurrounding said coke passage, means for passing theelectricl current through the chargev within the working chamber, ahorizontal top plate supported by said structure and providedwitlrsuperposed .hoppers in communication nwith the upper ends of said cokepassage and rsaid ore passages respectively, and a hearth vbeneath theworking-chamber prouided with means for discharging metal and slag influid condition.

4. An electric smelting furnace of the stack type having, incombination, estructure of suitable heat-resisting materlal 1n closingthe working chamber and construct Sed with a cylindrical upper feedportion including a cylindrical outer wall and cylindrical hollow wallsconcentric therewith forming between them vertical feed pas-` sages forheat-conserving streams of ore on its way to the heat zone, a centralcircular wall inclosing a vertical flue-shaped coke 'passage and adownwardly flaring circular wall separating inner and outer orepassa-ges surrounding said colte passage, means for passing the electriccurrent through .the charge within the working chamber, meansforcirculating the gases within the furnace .including gas spaces withinsaid hollow ore passa-ges, and a discharge pipe leading from said gaschamber.

5. An electric smelting furnace of the stack type having, incombination` a suitable hearth, a superstructure of suitable heat-resisting material inclosing a working chamber and constructed with acylindrical upper feed portion including a central circular wallinclosing a vertical flue-shaped coke passage, a downwardly flaring andapertured circular wall separating inner and outer ore passagessurrounding said coke passage and radial partitions dividing said or-epassages, a horizontal top plate supported by said superstructure andprovided with feed openings in communication with the upper ends of therespective ore passages, and partitions beneath said top platesubdividing portions of said outer ore passages into chutes leadingseverally to apertures in` saiddownwardly flaring wall.

6. An electric smelting furnace of the stack type having, incombination, a suitable ported by said superstructure and providedl withfeed openings in communication with the'upper endsot' the vrespectiveore passages, and partitions of suitable sheet material suspended fromsaid top plate subdividing portions of said outer ore passages intochutes leading severally to apertures 'in i said downwardly Haring wall.

7. An electric smelt-ing furnace of the stack type having, incombination,astruc ture of suitable heat-resisting material inclosingthe working chamber and constructed with a cylindrical upper feedportion including a cylindrical'outer wall and cylindrical wallsconcentric therewith forming between them vertical feed passages forheat conservingstreams of ore on its way to the heat zone, a centralcircular wall inclosing aV vertical flue-shaped coke passage, adownwardly flaring circular wall separating inner andouter ore passagessurrounding said coke passage andradial partitions dividing said innerand outer ore passages, a horizontal top plate support-ed by saidstructure and provided with feed openings in communication with theupper ends of said coke passage and said ore passages respectively,means beneath the several outer ore passages at the sides of the workingchamber for contracting the charge to t-he required extent in thevicinity of the heat zone, and a hearth beneath the center of theworking chamber provided with means for discharging metal and slag influid condition.

8. An electric smelting furnace of the stack'type having, incombination, a structure of suitable heat-resisting material inclosingthe working chamber and constructed with a cylindrical upper feedportion including a cylindrical outer wall and cylindrical Vwallsconcentric therewith forming between them vertical feed passages forheat-conserving streams of orelon its way to the heat zone, a centralcircular wall inclosing a vertical flue-shaped coke passage, adownwardly flaring circular wall separat-- ing inner and outer orepassages surrounding said coke passage and radial partitions dividingsaid inner and outer ore passages, a horizontal top -plate supported bysaid structure and provided with feed openings in communication with theupper ends of said coke passage and said ore passages respectively, alhearth of less diameter beneath the center lof the working chamberprovided with means for discharging metal and slag in fluid condition,and inclines beneath the several outer ore passages at the sides of theworking chamber extending inward and downward in line with the sides ofthe heart-h.

9. in electric siuelting furnace of the stack ltype h ving. incombination, a suitable hearth, a superstructure having a metallic shellinclosing a working chamberabove said hearth and feed passagesdischarging into said working chamber. steniless horizontal electrodesof the requisite size rectangular in cross section extendimr into saidworking chamber iunnediately above said hearth, and metallic electrodecollars includ- A ing rectangular frames tixedly'att-ached to said shelland suitably insulated therefrom.

movable sections within saidv frames tightly vclosing the openingsaround the several .electrodes, and means for retracting said sectionsto free the electrodes.

l0. An electric smelting furnace of the stack type having, incombination, a suitable hearth, a superstructure having a metallic shellinclosing aI working chamber above said hearth and feed passagesdischarging into said working chamber, stemless horizontal electrodes ofthe requisite size rectangular in cross section extending into saidworking chamber immediately above said hearth and metallic electrodecollars including rectangular frames ixedly attached to said shell andsuitably insulated therefrom, movable sections within said franz-estightly closing the openings around the several electrodes, means forretracting said sections to free the electrodes, and means for feedingthe electrodes endwise through said collars to take up wear.

11. An electric smelting furnace of thel stack type having, incombination, a suitable hearth, al superstructure having a metallicshell inclosing a working chamber above said hearth and ,feed passagesdischarging into said working chamber, stemless hoiizontal electrodes ofthe requisite size rectangular'in cross section extending into saidworking chamber. immediately above said hearth, and metallic electrodecollars including rectangular frames fixedlyattached to said shell andsuitably insulated therefrom, mo rvable sections within said framestightly closing the openings around the several electrodes, means forretracting said sections to free the electrodes, and means for adaptingthe electrodes to be built n situ and for feeding them endwise throughsaid collars to take up wear.

l2. An electric smelting furnace ofthe stack type having, incombination, a suitable hearth, a superstructure inclosing a workingchamber above said hearth and feed passages discharging into saidworking chamber, stemless horizontal electrodesof the requisite sizerectangular in cross section and built up of relativeliT smallrectangular carbons breaking joint longitudinally and cemented andcompressed into a` practically homogeneous mass, electrode collarshaving movable sections which normally close the openings around theseveral electrodes, means for retractingsaid sections to free theelectrodes. andgmeans for adapting the electrodes to be built situ andfor feeding them endwise through said collars.

13. An electric smelting furnace having, in combination, a suitablehearth` a superstructure inclosing a working chamber above said hearthand feed passages discharging into said working chamber. steinlesshorizontal electrodes of the requisite size rectangular in cross sectionbuilt up relapressed intoa practically homogeneous mass.

electrode collars including movable sections at the several sides ofeach electrode, means for' retracting said sections to free the eleotrodes, and means for feeding said electrodesv endvvise through saidcollars including an endwise movable mold adapted to be used'in thebuilding upoperation and provided With clamping devices 4for compressingthe elec trode vertically` and transversely and for keeping its parts.in ing. operation.

`14. In an electric smelting furnace; a-

stemless horizontal electrode rectangular in cross section built up ofrelatively small rectangular units including a tubular unit placeyduring the feed? which forms a longitudinal passage for the introductionof oxidizing material therethrough.

15. In an v electric smeltingl furnace a stemless horizontalv electroderectangular in cross section, composed of 'relatively small rectangularunits including al centraltubular' unit of re clay or the like in shortindisage `for the introduction of oxidizing material therethrough, theother units.r being of electrode carbon, substantially as hereinbe forespecified. v V

EDWARD R. TAYLOR.A Witnesses:

WILLIAM NJWISE, JOHN J. RUDMAN.

lvidually Ldetachable sections built into the electrode and forming alongitudinal pas.

